Lead testing machine for spiral gears



, .July 7, 1936. I J, c, DR DER 2,046,506

LEAD TESTING MACHINE FOR SPIRAL GEARS Fiied Nov. 16, 19:51 5 Sheets-Sheet 1 INVENTOR Joseph C -Drade;r

A ORNEY Julyf7, 1936.

J; C. DRADER LEAD TESTING MACHINE FOR SPIRAL GEAR Filed Nov. 16, 1931 5 Sheets-Sheet 2 July 7,1936. J. c. DRADER LEAD .TESTING MACHINE FOR SPIRAL GEARS Filed Nov. 16, 1951 5 Sheets-Sheet s INVENTOR Jsepi? CI .Drdder! BY v a QM g/zwb.

ATTORNEYS Patented July 7, 1936 FFME LEAD TESTING MACHINE FOB SPEAK; GEARS Joseph 0. Drader, Detroit, Mich, assignor, by mesne assignments, to Michigan Tool Company, a, corporation of Delaware Application November 16, 1931, Serial No. 575,195

14 Claims.

This invention relates to machine tools and particularly to a machine for checking the accuracy of articles having spiral threads, cutting teeth, or other projections having a helical lead, such like.

In Patent No. 1,898,084, granted February 21, 1933 on my co-pending application, Serial number 232,226, filed November 10, 1927, and assigned to the I have described and claimed a machine of the above mentioned type wherein the article to be testedwas rotated in relation to the longitudinal movement of an instrument which checked the accuracy of the spiral gears or hobs having a sharp lead angle. Difficulty heretofore experienced with machines of this type, when endeavoring to obtain the related movement of the article and the checking instrument by a lead screw and/or'a train of gears, was overcome by the structure of the above noted co-pending application through the employment of an accurately constructed rack which eliminated any play in the driving mechanism which'eiiected the rotation of the article and'the longitudinal movement of the checking instrument.

In practicing my invention, I am able to effect the related rotational and longitudinal movement between the article andthe checking instrument independent of the means employed to drive the various elements of the machine and for this reason any type of driving mechanism, such as -a lead screw, may be utilized irrespective of the amount of back lash eiiected thereby, since the relation between the rotation of the articleand the longitudinal movement of the checking instrument is entirely independent of the driving means.

The main objects of myinvention are-to provide an improved machine for checking the accuracy of the spiral lead of an element, which is extremely accurate and simple in construction and operation; to provide an improved machine wherein relative rotational and longitudinal movement between an article and an indicating instrument is efiected independent of the actuating mechanism which may be employed for producing the movement; to provide driving means between two a gularly movable tables which is adjustable to regulate the degree of movement therebetween, to interconnect the driven table with the support for the work to effect its ro-' tation; and in general, to provide a. lead testing machine which is extremely accurate, simple in operation and economical o1 nmnuiacture.

for example, as gears, cutters, and the assignee of the present invention,

Other objects and features of novelty of the invention will be either specifically pointed out or will become apparent when referring, for a better understanding of my invention, to the following description in conjunction with the ac companying drawings, wherein:

Figure 1 is a view, in endelevation, of a lead testing machine embodying features or my invention,

Fig. 2 is an enlarged broken view, in vation, of the machine illustrated in Fig. 1,

Fig. 3 is a plan view. oi'the structure illustrated in Fig. 2,

Fig. 4 is a sectional view of the structure illus- Side elel trated in Fig. 1, taken on the line 4-4 thereof; 15

Fig. is an enlarged view of the indicating device illustrated in Figs. 1, 2, and 3,

Fig. 6 is a broken view, in elevation, of a supporting arm and attachment for the indicating device illustrated in Fig. 5 showing a modified form thereof,

Fig. 7 is an end view of the structure illustrated in Fig. 6,

Fig. 8 is a sectional view of the structure illustratedin Fig. 6, taken on the line 8-8 thereof,

Fig. 9 is a sectional'view of the structure illustrated in Fig. 6, taken on the line 9-9 thereof, Fig. 10 is a. sectional view of a further modi fled supporting structure for supporting the indicating device illustrated in Fig. 5, and Fig. 11 is a sectional view of the structure illustrated in Fig. 10, taken on the line lI-H thereof.

My invention comprises in general amachine III, which includes a base I I, upon which carriages l2 and 13 are mounted for relative movements laterally of each other. The base II has a. rearwardly and laterally extending portion I which is further extended upwardly at each end to constitute bearings l 5 which support a shaft l6 upon which a. work supporting member I1 is mounted. The work supporting member I1 is mounted to have the work supporting portion so related. with the carriage l3 as to revolvethe work in relation to the longitudinal movement of a tool or an indicating mechanism I 8 which is associated with the carriage l2.

A guide slot is provided in the upper surface ofthe base II in which a rail 2|,ontheumlerside of the carriage I2, registers for guiding the movement of the carriage to the right or left as viewedin Fig. 2. A hand wheel '22 is supported on the front of the base member, on a. shaft 23 which extends to within the inner hollow surface otthebase. Uponthelnnerendoftheshaftdb the surface of the'arm-33.

Nuts 4| are screwed upon the sine bar.

2 23 a beveled gear 24 is supported in fixed relation thereto for rotation with the hand wheel 22.

'A lead screw 25 is supported on the base II by brackets 26 and 21 in longitudinal relation to the table l2, from the underside of which a threaded projecting portion 28 is provided in engagement with the thread of 'the lead screw 25. A bevel gear 29 is mounted in fixed relation .to the lead screw 25, in mesh with the bevel gear 24, for the purpose of transferring wheel 22 and the shaft 23 to the lead screw 25. The rotation of the lead screw 25 causes the threaded portion 28, associated therewith, to move the table 12 relative to the movement of the hand wheel 22.

An arm 36 is attached to the carriage l2 by a bolt 3|, said arm extending upwardly therefrom to form a split boss 32 having an aperture through which the supporting arm 33 of the indicating mechanism l6 projects and which is clamped in firm relation to the arm 30 by a bolt 34 which draws the sides of the boss into firm relation with The upper surface of the carriage i2 is provided with'arcuate T-shaped slots 35 which are struck on a radius from a point disposed centrally of the carriage. A bar 36 which has been designated in my above-mentioned co-pending application, and which will be referred to hereinafter as a sine bar is. mounted on the top surface of the carriage by supporting bosses 31. The bosses engage the ends of the bar and are provided with feet 38 having bolts 39 extending therethrough in such manner that the heads of the bolts register in the T-slot 35 provided in the carriage. the projecting ends of the bolts for clamping the feet 38 into firm relation with the top surface of the carriage.

This construction permits the adjustment of" the sine bar as to any predetermined angle relative to the movement of the carriage l2 for a purpose which will be explainedfullyhereinafter. In order to effect this angular adjustment of the sine I have provided an extension 42 on one of pin 43 therein for aiding the accurate setting of A flange 44 projects from "the carriage l2 adjacent to the projection 42 and is provided with a plurality of apertures 45 for the purpose of receiving pins which may be provided with extending, arms of predetermined dimensions, which are engageable by the head of the pin 43 to position the sine bar in a predetermined. angular position on the carriage.

The pins having the extending arms, are employed when a plurality of predetermined settings are repeatedly utilized, and when any other setting is desired, a pin may be provided in an aperture 45 having a head of known diameter, between the surface of which a d the head of the pin 43 the angular disposition of the sine bar may be accurately set off. The apertures are provided on the center line and at predetermined distances either side thereof tofacilitate the measuring of the angle to effect the disposition of the sine bar on either side of a center line through the carriage.

A frame membe a1 straddles the carriage l2 and extends upwardly from the base H for the which are mated with theraceways 46, between which a plurality of balls 5| are mounted upon which the carriage i3 rolls. To effect the moveas shown in Fig. 3, for

the rotation of the hand fit between the bosses terial or mayhave a centering pin 64 The arbor or the-center pin is, in this bracket 52 projects from the underside thereof into intimate engagement with the sine bar 36. A recess 53 is provided in the bottom end of the projecting member 52 to receive the sine bar, the side edges of the recess being of arcuate shape, permitting the angular adjustment'of the sine bar relative to the projecting'member 52.

As the sine bar is moved to the right or left with the carriage l2, the angular disposition of the bar causes the frontwardly or rearwardly movement of the carriage l3, an amount which is proportional to the angular disposition of the bar relative to the path of movement of the carriage l2. A pair of rails 55 are mounted at the edges of the top surface of the carriage l3 in parallel relation to the raceways 68 and49 and have their top surfaces very accurately machined relative to each other throughout their length. 1

The work supporting member I! is provided with a shaft engaging portion 56 of such length as to l5. A frontwardly portion member 56 and terminates through which'a rotatable is supported for rotational 51 extends from the in a hollow sleeve 58 shaft 59 extends and are mounted in fixed relation to the shaft 59 arh'ar cent to each end of the sleeve 58. The rolls or wheels 62 may be made entirely of friction mafriction material provided on the outer surface in engagement with the surface of the rail 55.

The right hand end of the shaft 59, as viewed in Fig. 2, is provided with a tapered aperture or other well known expedient for supporting a work or a work supporting arbor (not shown). manner, mounted in fixed relation to the shaft 59 to rotate along therewith. An arm 66 extends from the sides of the centering pin 64 for the purpose of engaging an arm on a dog attached to the shaft employed for supporting the work piece, for the purpose of rotating the work piece along with the centering spindle.

The inner surface of the shaft engaging portions 56 of the work supporting member I1, is provided with a pair of rails 61 which are engaged by the dovetailed slot 68 provided on the end of an 'arm 69 which supports a centering spindle II in alignment with the centering spindle 64. The centering spindle is mounted in a boss 12 which is biased into engagement with the supporting shaft for the work piece, by a spring 13 which is'withdrawn therefrom by a cam 14 operated'by a handle 15. A thumb nut 16 is employed for clamping the spindle H in any of its positions., The engagement between the dovetailed slot 68 and the rails 61 permits the adjustsurface of the rails 55. As thecarriage i3 is moved fron'twardly or rearwardly, the rolls or wheels 62 are revolved thereby to cause the shaft 59 to be rotated in one orthe other direction. This causes a predetermined relationto exist between the rotation of the shaft 59 and the longitudinal movement of the arm 30 relative movement of the-tables i3 and I2. Since the relative movement between the two carriages because of the the longitudinal movement of the 'arm 30 may likewise be relatively changed in accordance wit the helical lead of the work piece.

While it is to be-understood that my machine tool thus far described may be employed for any number of purposes where extreme accuracy is desired when operating on a work piece relative to its radial and longitudinal dimensions, I have illustrated one desirable utility of the machine, that ofchecking the accuracy of the spiral lead of a thread provided on the surface of a. work piece.

The indicating device I8, which is employed with the machine herein described, includes the supporting arm 33 hereinabove mentioned which may be clamped by the split boss 32 and the nut 39 in fixed predetermined relation to the arm 30.

A slotted. bar 18 is provided with a boss 19 which by a bolt 83.

A gauge supporting plate 86 is pivoted by a pin, .81- to the member 82, which is adjustable about the pin 81 through the adjustment of the thumb screws 88 which engages a tenon 89 projecting from the rear portion of the member 82. A pair of gauges 9| are mounted on the member 86 in oppositely disposed aligned engagement to each other, having the actuating plungers 92 thereof engaging the opposite sides of a multiplying bar 93 which is pivoted between a pair of arms 94 provided on the inner end of the plate 86. Projecting inwardly from the pivot, the bar 93 is extended and united with a ball shaped end 96 which engages the side of a tooth, slot or similar projection or indentation having a spiral lead, the accuracy of which is to be measured.

A slot 98 of T-shape is provided onthe edge of the carriage I2 in which the head of the bolt 3| is recessed and which is slidable along the slot for the purpose of adjusting the arm 30' relative to the diameter of the work piece. After the arm has been so adjusted a nut 99 may then be rotated to clamped position for retaining the arm in fixed position. A collar I00 is provided on the arm 33, having a set screw IOI therein, for the purpose of adjusting the vertical position of the arm 33 'relative to the arm 30 and the work piece. The operation of my machine will now be described. Assume a work piece I02 is mounted,

by means of a shaft I03 or a stub-arbor (not shown), in rotatable relation to the shaft 59, and that the arm 30 has been adjusted relative to the carriage I2 to have the ball end 96 of the -multiplying lever 93 in rubbing relation to .the

underside of a thread of the work piece I02. The gauge 9| is set to have its indicating arm I05 directed to-the zero point of the scales IOQ. The hand wheel 22 is then rotated to have the carriage I2 and, therefore, the arm 30 and the checking mechanisms I8 move parallel ment to be gauged.

It is to be understood that the sine bar 36 has been adjusted relative to the spiral lead provided on the work to have the carriage l3 move laterally with respect to themovement of the to the elecarriage I2 for the purpose of rotating the shaft 59 and, therefore, the work piece I02 in timed relation to the lateral movement of the checking device I8.

As the work piece I02 is rotated, the surface engaged by the'ball end 96, as it moves laterally across the work piece should, ii the work is accurate and the machine properly adjusted, engage the ball in the same horizontal plane. When this occurs no vertical movement of the ball is effected and the arms I05 of the gauges remain directed to the zero point ofthe scale. When inaccuracy in the spiral lead is present in the work piece, the ball 96 will be deflected vertically by an amount proportional to the inaccuracy of the lead which will be multiplied by the lever 93 to effect a large movement of the indicating arms I05 over the scale I 86. After one tooth has been checkedin this manner, the arms 69 and 5'5 are then raised about the shaft I 8, to disengage the wheels 62 from the surface of the rails 55 so that the work piece I02 may be adjusted to have an adjacent tooth brought into engagement with the ball 96 to have the checking thereof effected in a like manner. I

Referring to Figs. 6 to 9 inclusive, I have illustrated a modified form of retaining arm and element for supporting the indicating device in such manner as to have the device tiltable in alldirections. The purpose of this construction is to permit the ball end 96 of the lever 93 to engage the thread or tooth in such manner as to have the plane in which the lever 93 oscillates to be substantially at right angles to a tangent to the slope thereof. The arm 30 has a pin I01 extending through the split boss 32 thereof and is provided with an eye or aperture I08 through which a rod I09 extends to be. clamped therein by a screw III which draws the sides of the split end of the pin I01 together, tightly about the rod I09. A bracket H2 is mounted to slide upon the rod I09 and to be clamped thereto in'any predetermined position by a bolt I I3 which draws the parts of the bracket together about the rod. The upper end of the bracket is provided with an aperture H4 through which a bolt I I5 extends to engage an aperturedarm H8 provided on the indicating device I8.

In this construction it will be noted that the indicating device I8 is revolvable about the bolt H5 in one plane and that the bracket H2 is revolvable about the rod I09 in a plane degrees thereto and that the pin I01 is revolvable relative to the bushing 32 to provide a movement for the device I8 in a third plane. It will also be noted that the device I8 is adjustable on the rod I 09 which is also adjustable longitudinally of its length relative to the pin I01. In this construcany adjustment of the device I 8 may be made to position it at any angle or in any plane. When the thread or tooth of a gear is provided with a sharp lead, the device l8 may be tilted about the pin I I5 to have the plane through the path of movement of the lever 93 substantially at right angles to the thread so that any variations thereof may be noted on the index scale of the device. Any other adjustment necessary to bring the ball point 96 in predetermined engagement with the side of the tooth or thread, may be made through the adjustment of the pin 101, the rod I09 and the bracket II2 as has been pointed out hereinabove.

Referring to Figs. 10 'and 11 I have shown a further modified form of supporting arm for the 75 tudinal movement of the indicating device relative to the rotation of the gear should be reduced and the structure illustrated in Figs. and 11 is provided for this purpose. An auxiliary table -II8 is attached to the frame 41 by bolts II9 which are adjustably retained in the T slots I2I provided in the end of the frame 41 parallel to the T slots 98 in the carriage I2. The bracket is provided with an arm I22 for bracing the table and for providing a boss I23 to which a lever I24 is attached by a pivot I25. The upper surface of the table is provided with raceways I26 having balls I21 contained therein by the complementary raceways I28 supported on the under surface of a movable platform I29. A bracket I3! is supported on the movable carriage I2 by a bolt 3I. r

The lower end of the lever I24 is provided witha pin I32 which is recessed in a slot I33 in a plate I34 supported on one web of the bracket I3I. The upper end of the lever I24 is pivoted by a pin- I35 to the platform I29, the distance between the pivot I25 and pin I35 being substantially onehalf of the-distance between the pivot I25 and the pin I32. In this construction when the carriage I2 is moved, the lever I24 is rocked about the pin I25 to thereby move the platform I29 one-half of the distance of movement of the carriage I2.

- A cylinder I36 is provided on the other side or the table H8 in which a weight I31 is suspended on .a cable I39 which extends over a pulley HI and is attached to the under side of the platform I29 at I42. Thepurpose of the weight is to take up the slack in the pins of the lever I24, the car- I29, to thereby provide for the accurate movement of the platform relative *to the movement of the carriage by eliminating riage I2 and platform the backlash from between the moving elements.

A T slot I43 is provided on the top of the platform I29 in which a bolt I44 is slidably retained for securing an 'L-shaped bracket I45 on the platform. A slotted link I46 is supported on thearm -,I4'I of the bracket I45 upwardly extending and is secured thereto by a bolt I48. The upper end of the link I46 receives an'arni I49 of the indicating device I8 which is secured to the, link by a bolt I5I. In this construction, the indicating device I8 maybe revolved about the bolt I5I or about the bolt I48 or both so as to position the ball end 96 relative to the thread or tooth in such manner as to have the lever ,93 so related to the thread as to have the plane through which the lever moves, positioned substantially 90'degrees to the thread. I

When so mounted, a'ny irregularity in .the surface of the thread will be magnified by the indicating deviceto a greater extent than if the plane of movement of the arm were disposed at an angle to the thread which has been the practice heretofore. It will be further noted that the rotation of the gear relative to the movement of the indicating device will be twice that of the rotation of the gear and movement of the device, when the structure shown in Figs. 1 to 9 inclusive is employed, that is to say, when the indicating device is carried directly by the carriage When any of the structures herein illustrated and described are employed, exceedingly accurate checking of the curvature of the surfaces on a work piece results without requiring a skilled operator or the expenditure of time and labor in setting up the work piece and testing the accuracy of its-surfaces.

It is to be understood that the testing of the helical lead may be effected during the movement 5 of the table I2 in either direction, since the opposite rotation of the workpiece I02 will occur because of the reverse lateral movement of. the table I3 with respect to the movement of the table I2. The operation of my machine in both directions is made possible since the play in the lead screw 25 has no influence on the related movement in rotation of the work piece relative to the longitudinal movement of the checking device. The relation between the work piece and the checking device remains the same in either direction of movement'of the carriage I2 because no play is present between the sine bar, the projecting member on the carriage I3 which engages the sinebar, or between the rails of the carriage I3 and the wheels 62 for rotating the work piece. While I have described and illustrated but a single embodiment of my invention, it will be apparent to those skilled in the art that various changes, omissions, additions and substitutions 25 may be made therein without departing from the spirit and scope of my invention, as set forth in the accompanying claims.

I claim: I v 1. In a machine of the class described, a base having a carriage movable thereon and provided with an extension, an arm. adjustably supported on said carriage, a tool adjustably supported on said arm, a sine bar adjustably carried by said carriage, a second carriage movable laterally of 35 the direction of movement of said first carriage, having means for slidably engaging said sine bar rails on said second carriage, a support for a. work piece rotatably mounted on said extension of said base, and friction wheels engaging said rails and operatively connected to said work piece support. v v

2. In a machine of the class described, a base having a carriage movable thereon and provided with an extension, a tool carrying arm adjustably supported on said carriage, a second carriage movable laterally of the direction of movement of said first carriage and provided with rails, means interconnecting said carriages for efiecting their relative movement, a support'for a work piece rotatably mounted on said extension of said base sets of guide rails which are disposed angularly relative to each other in difierent parallel planes, a base for supporting said rails, carriages mounted on said rails, a tool supporting arm adjustably mounted on one of said carriages, means for moving said carriage, an' adjustable means on 0 said carriage for moving said other carriage angularly with respect to the movement of said first carriage during itsactuation, a work piece supporting member rotatably supported on said base, and interconnecting means including rollers be- 5 tween said second carriage and said work piece support member for effecting its rotation upon movement of said second carriage.

4. A machine for testing the accuracy of curved projections of work pieces including, in combina- 7 tion, a movable carriage, indicating means carried thereby, a carriage movable in angular relation to said first carriage, driving means between said carriages, -a. work supporting spindle, and rollers engaging said second carriage and driven 7t by. the movement thereof for driving said spindle relative to the movement of said first mentioned carriage.

5. A machine for testing the accuracy of curved surfaces of work pieces including, in combination, a movable carriage, indicating means carried thereby, a carriage movable at right angles to said first carriage, adjustable driving means beporting spindle, and rollers in connection with said spindle and in contact with said second carriage for effecting the rotation of the work relative to the movement of the second mentioned carriage.

7. A machine for testing the accuracy of curved surfaces of work pieces, including, in combination,

two carriages movable in angular relation to each other, a rotatable support for the work piece, rollers associated with said support for engagement with one of said carriages for effecting the o dicatingmeans.

rotation of the work piece relative to the move.- ment of the carriage, indicating means carried by the other carriage, and interconnecting means between the carriages for effecting their relative angular movement in accordance with the lead of the surface to be tested.

8. A machine for testing the accuracy of curved surfaces of workpieces including, in combination, a movable carriage, indicating means carried thereby, a carriage movable at right angles to the direction of movement of said first carriage, adjustable means interconnecting said caniages and adjustable for regulating the relative movement therebetween, a rotatable support for a work piece, a roller associated with said support,

and a track provided, on said second carriage in engagement with said roller for rotating the workpiece relative to the movement of the in- 9. A machine for testing the accuracy of curved surfaces of work pieces including, in combination, a base, a first table movable relative thereto, driving means for said first table, a second table movable in angular relation to the path of movement of said first table, adjustable means can-ied by one of said tables for eifecting' the relative speed of movement of the other table, a third table movable in the direction of movement of said first table, means between said first and third tables effecting an unequal displacement of said third table simultaneous with and proportional to the displacement ofsaid first table, in'dicating meanssupported on said third'tabie and incontact with a work piece, and means for supporting and rotating said work piece in timed relation with the movement of said indicating means.

10. A machine for testing the accuracy of curved surfaces of work pieces including, in combination, a base, a first tablemovable relative thereto, driving means for said first table, a second table movable in angular relation to the path of movement of said first table, adjustable means carried by one .table for effecting the angular movement of the second table, means actuated I by the movement of said second table for rotating a work piece in timed relation to the movement of the first table, a third table actuated by the movement of said first table at a speed which is predetermined relative to the movement of said first table, and an indicating device carried by said third table which moves in contact with said work piece.

11. In a precision machine for testing curved surfaces of work pieces including, in combination, a base, two tables mounted on said base disposed for movement in angular relation to each other, friction means between said tables for eflecting their positive movement in synchronism, a rotatable work support, means frictionally engaging and driven by one of said tables for rotating said work support, indicating means carried by said other table, and means for driving one of said tables.

12. A machine for testing the accuracy of curved surfaces of work pieces, including, in combination, a base for said machine, a first carriage movably supported on said base, a second carriage supported on said base and movable in angular relation to said first carriage, adjustable driving means between said can-iages' for effecting relative movement therebetween, indicating means carried by said first carriage, a work supporting spindle rotatably supported on said base,

and means including rollers engaging said second carriage for rotating said spindle in timed relation to themovement of said second carriage.

' 13. A machine for testing the accuracy of curved surfaces on work pieces, including, in combination, a base for said machine, a first carriage movably supported on said base, a second .car-

riage supported on said base and movable in an-,

gular relation to said first carriage, adjustable driving means between said carriages for effecting relative movement therebetween, indicating means carried by said first carriage, a work supporting spindle, and means including rollers engaging said second carriage for rotating said spindle in timed relation to the movement of said second carriage.

14. A machine for testing the accuracy of JOSEPH C. DRADER." 

